Your Digest for Thursday, Mar 21, 2024 10:59 PM


GI tract embryology and referred pain


[!TIP] Mnemonic: Sweat - "musk"

Sweat glands have muscarinic receptors.


pro-renin (a proenzymes) is stored in the [[Nephrology miscellaneous#Overview of renal histology and function|Juxtaglomerular cells]] of the afferent arteriole and released in response to


Thyroid hormones are stored within follicles by being bound to thyroglobulin

[!INFO] Thyroid peroxidase
Has 3 function:

  1. Oxidation : I- to I2
  2. Organification: Linking of I2 to tyrosine residues of thyroglobulin
  3. Coupling reaction: Combination of iodinated tyrosine residues to form T3 and T4.
  4. 2 x DIT = T4, DIT + MIT = T3.
    Thyroid peroxidase is the enzyme inhibited by thionamides. (Carbimazole, propylthiouracil)
    High intrathyroidal concentrations, outlasting the plasma half life.
    More inhibition of iodine organification.
    Rash: Usually can be treated with antihistamine, stoppage of thionamide not required. Cross reactivity to different thionamide seen in 50%.

Type Cutoff for abnormal
Total Cholesterol >200 mg/dL
TG >150 mg/dL
HDL <40 mg/dL male, <50mg/dL female
LDL >100 (but depends on risk)
VLDL

There are many recognized mutations of the enzyme and degree of dysfunction varies widely.

  1. appearance on blood film - cells look elliptical.

[!TIP] Mnemonic: Warm is more severe
most of the body is warm;
body isn't usually cold -> so cold AIHA antibodies don't bind.

warm Cold
More severe
More common
If Infections -> Acute anaemia;
If Idiopathic -> Chronic anaemia.
IgG +/- C3d (degraded C3) IgM (very efficient at binding complement)
Coated RBCs engulfed in spleen: Extravascular HL Intravascular AND extravascular haemolysis (due to complement binding
IgM dissociates in warm circulation.
Only complement C3 detected on RBC in the lab.
This complement can be detected using a DAT test which uses anti-compliment antibodies.
Splenomegaly
Spherocytosis on BP (microspherocytes) + reticulocytes Marked aggluination at room teperature seen on BP
Automimmune causes: Idiopathic, SLE, CLL Infections: Mycoplasma, IMN; lymphoma, PNH
Alloimmune causes: FTR, HDN, drug induced (methyldopa) In some lymphoproliferative disorders, the IgM arises due to monoclonal expansion; This is called cold haemaglutinin syndrome (or disease)
First line treatment: glucocorticoids to be given immediately on reporting of DAT result. ?rituximab if refractory

Primary cold agglutinin disease (CAD) is caused by an underlying lymphoproliferative bone marrow disorder causing formation of monoclonal IgM. Hemolysis is caused by IgM antibodies that are most active in vitro at low temperatures. Patient can have acrocyanosis due to agglutination of red cells in cold peripheries.

[!TIP] A cold AIHA but is IgG based.


#2022GM-MAY/Q17
It is one of the 3 types of non leukemic myeloproliferative neoplasm:

⭐The Janus Associated Kinase proteins are proteins that are coupled to growth signal receptors on haematopoietic cells. When the receptors bind growth factors, they active the JAK proteins which in turn activate the STAT family of signal transducers. STAT dimers activate transcription of specific genes.

  1. and splenomegaly. - Ruloxitinib - oral JAK2 inhibitor; can reduce spleen size.

Aplastic anaemia


| Howell-Joly bodies | Sickle cell disease (due to hyposplenism) |
| Target cells | Hyposlenism, thalassemia, liver disease |
| Tear drop poikilocytes | myelofibrosis |
HowelJollybodies.png

Target cells:
TargetCells.png

  1. alpha and thalassemia
  2. Hyposplenism
  3. liver disease

#hepatosplenomegaly


characterized by characterized by hypokalemia, hypochloremia, metabolic alkalosis, and hyperreninemia with normal blood pressure


Anatomy of CNIII

It passes through the cerebral peduncle and red nucleus on it's way out.
cerebralPeduncleMidBrain.png

cerebralPeduncle.png

midbrainCranialNerveIIIOcculomotorNerve.png

Posterior communicating artery aneurysm

posteriorCommunicatingArteryAneurysmPCOM.png
Usually arises at the junction of the PCOM and the internal carotid (as shown above).
circleOfWillisOpticTractNerves.png
cavernousSinusAnatomy.png
CNIII enters the orbit through the superior orbital fissure.

The CNIII can be affected by herniation of the temporal lobe in increased intracranial pressure.


ErythemaGyratumRepens.png
highly associated with malignancy, most commonly lung cancer. Source
Has a characteristic 'wood grain' appearance.



[!INFO] Inheritance
MEN1 and MEN2 are #autosomalDominant


Paraganglioma Phaeochromocytoma
head and neck Adrenal medulla
Noradrenaline Adrenaline and noradrenaline
More associated with genetic syndromes Can be associated with MEN2
Associated with succinate dehydrogenase gene mutations
Higher malignancy risk

Hence the lightning bolt

BNP - secreted by ventricles
ProBNP is converted to active BNP and inactive NT-proBNP.
(mnemonic: NT = sounds like 'inactive')
ANP and BNP secretion stimulus is high ventricular filling pressure -> therefore, increased in HF.
[!INFO] Mnemonic: HF => NTproBNP ( the one with more letters -> rises more)

Preference of prescription of drugs in heart failure (HFpEF)

[!TIP] Mnemonic: first line drugs for heart failure => RBMS


- **sodium valproate**: associated with *neural tube* defects
- **carbamazepine**: often considered the least teratogenic of the older antiepileptics
- **phenytoin**: associated with **cleft palate**

#2015MCQ-APR/Q01
Cyclooxygenase (COX) is the rate-limiting enzyme in prostaglandin (PG) synthesis.